Slant hole well drilling apparatus



May 13, i969 c JENJQNS ETAL Filed July l, 1968 May 13, 969 Q JENKlNS ETAL 3,443,647

SLANT HOLE WELL DRILLING APPARATUS Filed July l, 1968 sheet ofs l 2a 47 l' i li :f i Y l f/2 /24 K i l l l i .w/

EL /f NVENTORS.

` ATTORNEYS.

May i3, i969 c. JENKlNs ETAI- SLANT HOLE WELL DRILLING APPARATUS Filed July l, 1968 m. Q m

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t mw, E s M www 3,443,647 SLANT HOLE WELL DRILLING APPARATUS Cecil Jenkins and Joseph R. Woolslayer, Tulsa, Okla., as-

signors to Lee C. Moore Corporation, Pittsburgh, Pa., a corporation of Pennsylvania Filed July 1, 1968, Ser. No. 741,612 Int. Cl. E21b 19/00, 7/04 U.S. Cl. 175-85 13 Claims ABSTRACT F THE DISCLOSURE Mounted on a well drilling platform is a pipe setback tower that supports a pipe rack. Also mounted on the platform beside the tower is a drilling mast that has an open side facing the pipe rack. The mast may be inclined upwardly and away from the tower but is connected with it by means of a walkway. At the lower end of the mast there is a rotary table support for holding an inclined rotary table for slant drilling` It is sometimes desirable to drill two or more wells without moving the substructure or drilling platform. One way of doing this is to move a vertical drilling mast to different locations on the platform for drilling the different wells. Another way is to tilt the mast so that a well can be drilled at a slant. A problem that arises in connection with slant drilling at a considerable angle to the vertical relates to the racking of the drill pipe on the setback in front of the mast. The ordinary racking platform and rack projecting from the front of an open front mast cannot be used because, in the tilted position of the mast, the rack is far to the rear of the setback area of the platform. One solution to this problem has been to support a racking platform a considerable distance in front of the mast on the end of a boom projecting from the mast, so that the rack will be over the setback. This requires the rack and outer end of the boom to be suspended by cables from the top of the mast, and the use of guy lines to steady the rack and the pipes stacked in it against wind loads. At best, such a system is not very stable.

It is among the objects of this invention to provide oil well drilling apparatus for slant drilling, in which the pipe rack is supported above the setback independently of the inclined mast, in which the mast can be supported in inclined position by the structure supporting the pipe rack, and in which the rotary table can be tilted with the mast to different angles without requiring adjustment of the driving chain for the table.

The preferred embodiment of the invention is illustrated in the accompanying drawings, in which FIG. l is a side view of the drilling apparatus;

FIG. 2 is a view from the mast end of the apparatus, but with the drawworks omitted for the sake of clearness;

FIG. 3 is a view from the opposite end;

FIG. 4 is an enlarged front view of the traveling block taken on the line IV-IV of FIG. l;

FIG. 5 is a cross section taken on the line V-V of FIG. 4;

FIG. 6 is a plan view of the drilling apparatus;

FIG. 7 is a plan view of the main platform; and

FIGS. 8 and 8 are enlarged details taken on the lines VIII-VIII and IX-IX of FIGS. 7 and 6, respectively.

Referring to the drawings, a base, substructure or platice form 1 is positioned at a drilling site in any suitable manner. For offshore drilling, the platform is mounted on a structural steel framework 2 that extends above the water. Mounted on the central area of the platform and extending upwardly and outwardly therefrom over the rear end of the platform is a drilling mast 3 that has a back and forwardly extending sides. The three sided mast has an open front side facing the front end of the platform. At the lower end of the mast there is a support 4 for a rotary table 5. The support is inclined in order to hold the table at the same inclination as the mast. The upper end of the mast supports a crown block 7, over which lines 8 extend from a drawworks 9 on the platform to a traveling block 10 inside the mast. This block is supported on a dolly 11 that runs up and down a track 12 secured to the inner side of the back of the mast. The traveling block is attached to the dolly by a transverse pivot 13. The mast can be supported in various ways in inclined position, but preferably in a manner that will be described later.

The pipe setback 15, which is the area of the platform for supporting a stand of drill pipe, is between the rotary table and the front end of the platform, as shown in FIG. 7. Since the pipe must stand more or less vertically with their upper ends held in a pipe rack, it will be seen in FIG. 1 that the usual pipe rack projecting from the front of the tilted mast would be behind the lower end of the mast and therefore useless. It is therefore a feature of this invention that a pipe rack is used which is not supported by the mast, but is held above the setback by an independent structure. Accordingly, a setback tower 16 is mounted on the platform adjacent its front end in a position to hold a pipe rack above the setback 1S. The tower preferably has three closed sides, and an open back side facing the mast. The lower end of the front side of the tower may be mounted in shoes 17 on the platform, and the rear edges of the parallel sides of the tower may be inclined upwardly and rearwardly from the shoes to the level at which the pipe rack is to be located, as shown in FIG. 1. From there the rear edges of the parallel sides may be inclined upwardly and forward to the upper end of the front side of the tower. The tower may be braced in upright position in various ways, but preferably by a pair of inclined braces 18 extending from about its pipe rack level downwardly and rearwardly past the opposite sides of the mast to shoes 19 on the rear end of the platform.

Supported inside the tower at the pipe rack level is a central rearwardly extending finger board 21, shown in FIG. 6, on the opposite sides of which there are rows of laterally spaced pipe rack bars 22 extending from the sides of the tower inwardly toward the finger board to form the pipe rack. It will be seen that the rack is above the setback 15 so that pipes in the rack can stand on the setback.

To remove a pipe from the mast to the rack after the lower end of the pipe directly above the rotary table has been disconnected from the pipe below as shown in FIG. l, the free end of a catline 23 is attached to the pipe. This line extends up and over a sheave 24 supported by the tower and then down to the vvcathead 25 of the drawworks. The catline supports the lower end of the pipe as it is guided to the setback and lowered onto it by the traveling block. The upper end of the pipe then is released from the usual elevator 26 and pulled forward by a line 27, previously fastened to the pipe, into the setback tower where the pipe can be placed in the pipe rack. This pull line extends from the upper end of the pipe forward and over a sheave 28 supported bythe top of the tower, and then down to the platform where is can be reeled in or let out by any suitable means, such as by an air hoist 29.

To permit a workman to move back and forth between the inclined mast and the pipe rack as pipes are racked and unracked, the upper part of the tower is connected with the mast by an intervening walkway 30. Preferably, the front end of the walkway is fastened to the setback tower at the level of the pipe rack, although it could be a little above or below it. It is desirable to form the walkway from two laterally spaced catwalks 31, between which the upper ends of the drill pipe can be swung back and forth between the inside of the mast and the pipe rack. -Each catwalk 31 is hinged to the pipe setback tower on a horizontal axis 32. As best shown in PIG. 9, the inner side of the opposite end of the catwalk rests on an angle bracket 33 secured to a sleeve 34 pivotally mounted on a trunnion 35 projecting laterally from the adjacent front leg of the mast. The catwalk is provided with a plurality of longitudinally spaced holes, through some of which bolts 36 extend that fasten the catwalk to bracket 33. At the mast ends of the catwalks small platforms 37 are removably connected to the front legs of the mast. Likewise, small triangular platforms 38 are removably secured to side platforms 39 in the setback tower.

The two catwalks not only allow a man to work at either side of the walkway or provide for men on both sides of it, but they also enclose the area between the mast and setback tower so that there can be no danger of a pipe swinging laterally away from the walkway. Another important feature of this invention is that the Walkway can be used as a rigid tension member for supporting the mast in inclined position from the braced tower, whereby no other braces or suspension cables may be required for that purpose.

Although the mast can be mounted at a fixed angle to the platform, such as 30, it is a further feature that the angle can be changed in order to drill wells at different inclinations and even vertically. This can be accomplished by pivotally connecting the lower end of the mast to the platform on a transverse axis so that the mast can be swung toward and away from the setback tower. Thus, the back feet of the mast can be rigidly mounted on rotary table support 4, and the front feet can be mounted in brackets 41 (FIGS. 7 and 8) secured to the top of that support and also pivotally supported by bearings 4Z mounted on platform 1 at opposite sides of the mast. By mounting the rotary table on support 4 in such a position that the laterally projecting drive shaft 43 of the table is concentric with the pivotal axis of the mast, the chain 44 that drives the sprocket 45 on the end of the shaft will not have to be adjusted when the angle of the mast is changed, because the position of the axis of the sprocket will not be changed when the mast is tilted. If it is desired to drill at a steeper angle than shown, the rear ends of the two catwalks are disconnected from mast brackets 33 and the mast then is swung the desired number of degrees toward the tower by lines 46 connected to the upper end of the mast and extending forward and down over sheaves 47 (FIG. 3) at the top of the tower to a winch 48 on platform 1. When the mast has reached its new position, such as the inclined dotted line position in FIG. 1, the catwalks are attached to brackets 33 again and it is supported by the catwalks. Lines 46 also can be used to help support the mast from the upper part of the tower. Of course, if desired, the mast can `be pulled up to upright position against the setback tower and attached tot it for vertical drilling, as also shown in dotted lines in FIG. 1. In that case the small platforms 37 and 38 first are removed 4 and the catwalks can be lowered onto inclined braces 18 as they will not be needed.

According tothe provisions of the patent statutes, we have explained the principle of our invention and have illustrated and described what we now consider to represent its best embodiment. However, we desire to have it understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically illustrated and described.

We claim:

1. Oil well drilling apparatus comprising a platform, a pipe setback tower mounted thereon, a pipe rack supported by the upper part of the tower, a drilling mast mounted on the platform beside the tower and having an open side facing the pipe rack to permit drill pipe to be moved back and forth between the mast and the rack, the mast being inclined upwardly and away from the tower, means extending between the mast and the upper part of the tower, and a rotary table support at the lower end of the mast for holding an inclined rotary table for slant drilling.

2. Oil well drilling apparatus according to claim 1, in which said means include a walkway leading to said tower adjacent the pipe rack.

3. Oil well drilling apparatus according to claim 2, in which said Walkway includes two laterally spaced catwalks, between which said back and forth movement of drill pipe can be effected.

4. Oil well drilling apparatus according to claim 2, in which said walkway connects mast and towers and forms at least some of the support for the mast in its inclined position.

5. Oil well drilling apparatus according to claim 1, including bracing for the tower inclined from the upper part of the tower downwardly past the mast to the platform, and means connecting the bracing to the tower and platform.

6. Oil well drilling apparatus according to claim 1, in which said tower has three closed sides and an open fourth side facting the mast, and said pipe rack is mounted inside the tower and is accessible from its open side.

7. Oil well drilling apparatus according to claim 1, including a sheave mounted on said tower above the pipe rack, and a line running over the sheave for effecting said back and forth movement of drill pipes.

8. Oil well drilling apparatus according to claim 1, including a rotary table mounted on said support, a sheave mounted on the tower, and a line running over the sheave and adapted to be connected to the lower end of a drill pipe directly above said rotary table to carry it to the base of the setback tower.

9. Oil well drilling apparatus according to claim 6, in which said open side of the mast is at its front, said apparatus including means pivotally connecting the lower end of the mast to the platform on a transverse axis, and means for swinging the mast forward to upright position behind said tower for vertical drilling when desired.

10. Oil well drilling apparatus according to claim 2, including means pivotally connecting the lower end of the mast to the platform on a transverse axis, means for swinging the mast forward the tower supporting the walkway, and backward to different positions, and releasable means connecting the walkway with the mast.

11. Oil well drilling apparatus according to claim 10, including means hinging the walkway to the tower on a transverse axis.

12. Oil well drilling apparatus according to claim 1, including means pivotally connecting the lower end of the mast to the platform on a transverse axis, means for swinging the mast forward and backward to different angles, said rotary table support being rigidly connected to the mast below said pivotal connecting means, a rotary table mounted on said table support and provided with a laterally projecting drive shaft concentric with said transverse axis, and a driving sprocket mounted on said shaft,

5 6 whereby swinging of the mast will not move the sprocket 1,884,874 10/ 1932 Ross 175-85 X radially. 2,792,198 5/1957 Braun 175-5 13. Oil well drilling apparatus according to claim 2, 2,803,434 8/ 1957 Heinish 175-85 X including means rigidly connecting said walkway to the 2,849,212 8/ 1958 Robbins 175-85 X mast and tower to hold the mast inclined, bracing for 5 2,919,899 1/ 1960 Hitchcock 173-40 the tower inclined from its upper part downwardly past 3,198,263 8/ 1965 Reischl 173-26 the mast to the platform, and means connecting the brac- 3,252,527 5/ 1966 Alexander 173-41 ing to the tower and platform. 3,280,920 10/1966 Scott 173-44 3,340,938 9/1967 Wilson 173-28 References Cited 10 3,368,699 2/ 1968 Scaggs 175-85 X UNITED STATES PATENTS NILE C. BYERS, JR., Primary Examiner. 739,860 9/1903 Harmon 175-85 X 

